Problem: Which of these numbers is composite? ${41,\ 77,\ 83,\ 89,\ 97}$
Answer: A composite number is a number that has more than two factors (including 1 and itself). 41, 83, 89, and 97 each have only two factors. The factors of 77 are 1, 7, 11, and 77. Thus, 77 is the composite number.